首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 109 毫秒
1.
The present note deals with the effects of seawater with different copper concentrations and pH values on the larvae of the barnacle Balanus reticulatus Utinomi. The results show that the higher the copper concentration and the lower the pH value in the seawater, and the more acute the toxicity. In the natural seawater of pH 8.1 the effective concentration EC_(50), i.e. the copper concentration causing 50%. larvae fail to attach, is approx-  相似文献   

2.
This paper deals with the geochemical characteristics of arsenic in sediments from Bohai Gulf. The arsenic in seawater, surface sediments and cores is determined. Also measured are other physical and chemical parameters, such as Ni, Fe, C, pH and Eh in sediments. The values of As range from 0.6 to 4.5 ppb in seawater, from 10.0 to 20.9 ppm in surface sediments and from 6.8 to 22.8 ppm in cores.The contents of As from south are higher than those from north. However the As in sediments is the element not affected by pollution.The adsorption and codeposition of Ferric oxide colloid are the major form of transference of As from seawater to sediments in Bohai Gulf.The valence state of As in sediments is HAsO42-  相似文献   

3.
Severe slugging can occur in a pipeline-riser system at relatively low liquid and gas flow rates during gas-oil transportation, possibly causing unexpected damage to the production facilities. Experiments with air and water are conducted in a horizontal and downward inclined pipeline followed by a catenary riser in order to investigate the mechanism and characteristics of severe slugging. A theoretical model is introduced to compare with the experiments. The results show that the formation mechanism of severe slugging in a catenary riser is different from that in a vertical riser due to the riser geometry and five flow patterns are obtained and analyzed. A gas-liquid mixture slug stage is observed at the beginning of one cycle of severe slugging, which is seldom noticed in previous studies. Based on both experiments and computations, the time period and variation of pressure amplitude of severe slugging are found closely related to the superficial gas velocity, implying that the gas velocity significantly influences the flow patterns in our experiments. Moreover, good agreements between the experimental data and the numerical results are shown in the stability curve and flow regime map, which can be a possible reference for design in an offshore oil-production system.  相似文献   

4.
Ferromanganese(Fe-Mn) crusts are potential archives of the Cu and Zn isotope compositions of seawater through time. In this study, the Cu and Zn isotopes of the top surface of 28 Fe-Mn crusts and 2 Fe-Mn nodules were analysed by MC-ICP-MS using combined sample-standard bracketing for mass bias correction. The Zn isotope compositions of the top surface of Fe-Mn crusts are in the range of 0.71‰ to 1.08‰, with a mean δ~(66) Zn value of 0.94‰±0.21‰(2 SD, n=28). The δ~(65) Cu values of the top surface of Fe-Mn crusts range from 0.33‰ to0.73‰, with a mean value of 0.58‰±0.20‰(2 SD, n=28). The Cu isotope compositions of Fe-Mn crusts are isotopically lighter than that of dissolved Cu in deep seawater(0.58‰ vs. 0.9‰). In contrast, the δ~(66) Zn values of Fe-Mn crusts appear to be isotopically heavy compared to deep seawater(0.94‰±0.21‰ vs. 0.51‰±0.14‰). The isotope fractionation between Fe-Mn crusts and seawater is attributed to equilibrium partitioning between the sorption to crusts and the organic-ligand-bound Cu and Zn in seawater. The Cu and Zn isotopes in the top surface of Fe-Mn crusts are not a direct reflection of the Cu and Zn isotopes, but a function of Cu and Zn isotopes in modern seawater. This study proposes that Fe-Mn crusts have the potential to be archives for paleoceanography through Cu and Zn isotope analysis.  相似文献   

5.
This article deals with a new method of analysing in seawater, i. e. the uranium is concentrated with an aqueous suspension of basic zinc carbonate, subsequently isolated and determined by extraction-photometric method. In concentrating uranium such factors as stirring time, amount of adsorbent used, acidity of seawater were studied and conditions suitable for analysis were found. This method is simple, accurate and good in reproducibility. It is not necessary to adjust the pH of seawater before analysis. This technique can also be applied to determination of uranium in river or lake.  相似文献   

6.
A cabled ocean observatory system that can provide abundant power and broad bandwidth communication for undersea instruments is developed. A 10 kV direct current (kVDC) with up to 10 kW power, along with 1 Gigabit/sec Ethernet communication, can be transmitted from the shore to the seafloor through an umbilical armored cable. A subsea junction box is fixed at a cable terminal, enabling the extension of up to nine connections. The box consists of three main pressure vessels that perform power conversion, power distribution, and real-time communication functions. A method of stacking modules is used to design the power conversion system in order to reduce the 10 kV voltage to levels that can power the attached instruments. A power distribution system and an Ethernet communication system are introduced to control the power supply and transmit data or commands between the terminals and the shore station, respectively. Specific validations of all sections were qualified in a laboratory environment prior to the sea trial. The ocean observatory system was then deployed at the coast of the East China Sea along with three in situ instruments for a 14-day test. The results show that this high voltage-powered observatory system is effective for subsea long-term and real-time observations.  相似文献   

7.
This article studies the application of the alternating current field measurement (ACFM) method in defect detection for underwater structures. Numerical model of the ACFM system is built for structure surface defect detection in seawater environment. Finite element simulation is performed to investigate rules and characteristics of the electromagnetic signal distribution in the defected area. In respect of the simulation results, underwater artificial crack detection experiments are designed and conducted for the ACFM system. The experiment results show that the ACFM system can detect cracks in underwater structures and the detection accuracy is higher than 85%. This can meet the engineering requirement of underwater structure defect detection. The results in this article can be applied to establish technical foundation for the optimization and development of ACFM based underwater structure defects detection system.  相似文献   

8.
This paper explores the accumulations ana distributions of Cd, Pb and Cu in clam Area granosa through determining their contents in Dlood and soft parts. The results show an order of concentration factors for these metals therein as: Cd>Cu>Pb; the values of concentration factors and the patterns of distribution are similar for Cu and Pb but different from Cd. Concentration factors in blood can reflect the enrichement abilities of soft parts. Exposure experiments have indicated that the Pb level in blood is controlled by Pb concentrations in surrouding seawater, changing with time, that the Pb cocentration causing poisoning in the seawater is 1-100 μg/1, and that the Pb content in blood and soft parts of Area granosa increases with that of Pb increasing in seawater. There exist relationships of double logatithmic concentrations for Pb among the three mediums.  相似文献   

9.
pH is a measure of the hydrogen ion activity in a solution, which is a function of temperature. Under normal seawater conditions, it is well constrained. Nowadays, with an increasing interest in complex environments(e.g.,sea ice), a better understanding of the temperature change on pH under extreme conditions is needed. The objective of this paper was to investigate the temperature coefficient of the seawater pH(?pH/?T) over a wide range of temperature, pH, dissolved inorganic carbon(DIC) and sa...  相似文献   

10.
O-phthaldialdehyde is used for the determination of free amino acid in seawater by measuring the fluorescence produced by its reaction with the a-amino group of amino acids. This method is so sensitive that as little as 1-10 nM of amino acids and less than 1 ml of seawater may be sufficient for one test.This method is simple, rapid and accurate and a-amino acids contained in seawater can directly be determined without concentration and extraction. It is free from the interference of large content of inorganic salts and other nitrogenous compounds in seawater.A hundred and fifty-two samples collected at 24 stations in offshore of Zhejiang have been analyzed. The results obtained show that the range of concentration of the total free amino acid is 0.37-4.70 μM. The values are high near shore and low offshore.  相似文献   

11.
We have developed new systems capable of profiling to >1000 m for measuring in situ pH and fugacity of CO2 (fCO2) in the ocean using spectrophotometric analysis (pH and CO2 profilers). The in situ pH is determined by detecting the color change of the pH indicator (m-cresol purple). It can withstand ambient pressure to 1000 m depth. The CO2 profiler analyzed in situ fCO2 by detecting the change of pH in an inner solution, equilibrated with the seawater through a gas permeable membrane. It can be operated to 2500 m depth. We used an amorphous fluoropolymer tubing form of AF-2400 for the gas permeable membrane due to its high gas permeability coefficients. The inner solution was a mixture of 2 μM bromocresol purple (BCP) and 5 μM sodium hydroxide. This system gave us a response time of 1 minute, which is twice as fast as previous systems. The precisions of pH and CO2 profilers were within 0.002 and 2.5% respectively. We have used these profilers to study the North Pacific, obtaining good agreement with the difference between the data from profilers and a discrete bottle of 0.002 ± 0.005 pH (SE, n = 25) and −0.4 ± 3 μatm (SE, n = 31).  相似文献   

12.
彭鹏飞  马媛  史荣君  王迪  许欣  颜彬 《海洋科学》2022,46(10):140-149
根据2018年7月、11月和2019年1月、4月对广东考洲洋牡蛎养殖海域进行4个季节调查获得的pH、溶解无机碳(DIC)、水温、盐度、溶解氧(DO)及叶绿素a(Chla)等数据,估算该区域表层海水溶解无机碳体系各分量的浓度、初级生产力(PP)、表层海水CO2分压[p(CO2)]和海-气界面CO2交换通量(FCO2),分析牡蛎养殖活动对养殖区碳循环的影响。结果表明:牡蛎养殖区表层海水中Chla、DIC、HCO3–和PP显著低于非养殖区;养殖淡季表层海水中pH、DO、DIC、HCO3–、和CO32–显著大于养殖旺季,养殖旺季的p(CO2)和FCO2显著大于养殖淡季。牡蛎养殖区表层海水夏季、秋季、冬季和春季的海-气界面CO2交换通量FCO2平均值分别是(42.04±9.56)、(276.14±52.55)、(–11.59±18.15)和(–13.02±6.71)mmol/(m2·d),冬季各站位FCO2值离散度较大,其中位数是–10.73mmol/(m2·d)。在全年尺度,表层海水p(CO2)及FCO2与水温呈显著正相关,与盐度呈显著负相关。在非养殖区,浮游植物光合作用可能对影响表层海水p(CO2)及FCO2起主导作用。养殖牡蛎钙化、呼吸作用等生理因素释放的CO2对表层海水p(CO2)及FCO2未产生显著影响。考洲洋养殖海域养殖旺季为CO2的源,养殖淡季整体为CO2的弱汇。  相似文献   

13.
Calcification in the marine environment is the basis for the accretion of carbonate in structures such as coral reefs, algal ridges and carbonate sands. Among the organisms responsible for such calcification are the Corallinaceae (Rhodophyta), recognised as major contributors to the process world-wide. Hydrolithon sp. is a coralline alga that often forms rhodoliths in the Western Indian Ocean. In Zanzibar, it is commonly found in shallow lagoons, where it often grows within seagrass beds and/or surrounded by green algae such as Ulva sp. Since seagrasses in Zanzibar have recently been shown to raise the pH of the surrounding seawater during the day, and since calcification rates are sensitive to pH, which changes the saturation state of calcium carbonate, we measured the effects of pH on photosynthetic and calcification rates of this alga. It was found that pH had significant effects on both calcification and photosynthesis. While increased pH enhanced calcification rates both in the light and in the dark at pH >8.6, photosynthetic rates decreased. On the other hand, an increase in dissolved CO2 concentration to 26 μmol kg−1 (by bubbling with air containing 0.9 mbar CO2) caused a decrease in seawater pH which resulted in 20% less calcification after 5 days of exposure, while enhancing photosynthetic rates by 13%. The ecological implications of these findings is that photosynthetically driven changes in water chemistry by surrounding plants can affect calcification rates of coralline algae, as may future ocean acidification resulting from elevated atmospheric CO2.  相似文献   

14.
There are serious concerns that ocean acidification will combine with the effects of global warming to cause major shifts in marine ecosystems, but there is a lack of field data on the combined ecological effects of these changes due to the difficulty of creating large‐scale, long‐term exposures to elevated CO2 and temperature. Here we report the first coastal transplant experiment designed to investigate the effects of naturally acidified seawater on the rates of net calcification and dissolution of the branched calcitic bryozoan Myriapora truncata (Pallas, 1766). Colonies were transplanted to normal (pH 8.1), high (mean pH 7.66, minimum value 7.33) and extremely high CO2 conditions (mean pH 7.43, minimum value 6.83) at gas vents off Ischia Island (Tyrrhenian Sea, Italy). The net calcification rates of live colonies and the dissolution rates of dead colonies were estimated by weighing after 45 days (May–June 2008) and after 128 days (July–October) to examine the hypothesis that high CO2 levels affect bryozoan growth and survival differently during moderate and warm water conditions. In the first observation period, seawater temperatures ranged from 19 to 24 °C; dead M. truncata colonies dissolved at high CO2 levels (pH 7.66), whereas live specimens maintained the same net calcification rate as those growing at normal pH. In extremely high CO2 conditions (mean pH 7.43), the live bryozoans calcified significantly less than those at normal pH. Therefore, established colonies of M. truncata seem well able to withstand the levels of ocean acidification predicted in the next 200 years, possibly because the soft tissues protect the skeleton from an external decrease in pH. However, during the second period of observation a prolonged period of high seawater temperatures (25–28 °C) halted calcification both in controls and at high CO2, and all transplants died when high temperatures were combined with extremely high CO2 levels. Clearly, attempts to predict the future response of organisms to ocean acidification need to consider the effects of concurrent changes such as the Mediterranean trend for increased summer temperatures in surface waters. Although M. truncata was resilient to short‐term exposure to high levels of ocean acidification at normal temperatures, our field transplants showed that its ability to calcify at higher temperatures was compromised, adding it to the growing list of species now potentially threatened by global warming.  相似文献   

15.
微藻固碳是一种新型节能减排技术，具有长期可持续发展的潜力。本文对两株富油微藻（球等鞭金藻和微拟球藻）进行了富碳培养下生长特性及中性脂积累特性的研究。两株富油微藻的最佳培养条件为10%CO2浓度和f培养基。本研究对两株富油微藻的最大生物量产率、总脂含量、最大油脂产率、微藻的C含量和CO2固定率进行了测定。球等鞭金藻的各参数指标分别为：142.42±4.58g/（m2·d），39.95%±0.77%，84.47±1.56g/（m2·d），45.98%±1.75%和33.74±1.65g/（m2·d）。微拟球藻的各参数指标分别为：149.92±1.80g/（m2·d），37.91%±0.58%，89.90±1.98g/（m2·d），46.88%±2.01%和34.08±1.32g/（m2·d）。实验结果显示，两株海洋微藻均属于高固碳优良藻株，适合应用于微藻烟气减排技术开发，具备用于海洋生物质能耦合CO2减排开发的潜力。  相似文献   

16.
The aim of this study was to investigate whether coral photosynthetic efficiencies and recovery processes are affected by CO2‐driven ocean acidification in symbiont photosynthesis and coral calcification. We investigated the effects of five CO2 partial pressure (pCO2) levels in adjusted seawater ranging from 300 μatm (pre‐industrial) to 800 μatm (near‐future) and strong and weak light intensity on maximum photosynthetic efficiency and calcification of a branching coral, Stylophora pistillata, as this species has often been used in rearing experiments to investigate the effects of acidified seawater on calcification and photosynthetic algae of corals. We found that, the photosynthetic efficiencies and recovery patterns under different light conditions did not differ among pCO2 treatments. Furthermore, calcification of S. pistillata was not affected by acidified seawater under weak or strong light conditions. Our results indicate that the photosynthetic efficiency and calcification of S. pistillata are insensitive to changes in ocean acidity.  相似文献   

17.
On the basis of the data of hydrochemical investigations of waters of the Sevastopol Bay, we discuss the results of the analysis of the carbonate system and the total alkalinity of seawater obtained by using two methods. By using the linear method of least squares, we compare the results of the analysis of the carbonate system according to pH values and the total alkalinity and according to pH values and dissolved inorganic carbon. It is shown that, within the investigated range of pH values, Alk, and TCO2, the mean relative deviations of values of the fugacity of CO2 and the concentrations of dissolved CO2 and CO32− ions computed by using different input parameters are equal to 3.0, 1.0, and 9.6%, respectively.  相似文献   

18.
The absorption of anthropogenic CO2 and atmospheric deposition of acidity can both contribute to the acidification of the global ocean. Rainfall pH measurements and chemical compositions monitored on the island of Bermuda since 1980, and a long-term seawater CO2 time-series (1983–2005) in the subtropical North Atlantic Ocean near Bermuda were used to evaluate the influence of acidic deposition on the acidification of oligotrophic waters of the North Atlantic Ocean and coastal waters of the coral reef ecosystem of Bermuda. Since the early 1980's, the average annual wet deposition of acidity at Bermuda was 15 ± 14 mmol m− 2 year− 1, while surface seawater pH decreased by 0.0017 ± 0.0001 pH units each year. The gradual acidification of subtropical gyre waters was primarily due to uptake of anthropogenic CO2. We estimate that direct atmospheric acid deposition contributed 2% to the acidification of surface waters in the subtropical North Atlantic Ocean, although this value likely represents an upper limit. Acidifying deposition had negligible influence on seawater CO2 chemistry of the Bermuda coral reef, with no evident impact on hard coral calcification.  相似文献   

19.
工业革命以来,人类活动释放的大量CO2进入大气层,不仅产生严重的温室效应,也使得全球海洋出现酸化的现象。造礁珊瑚被认为是受海水酸化影响最大的类群。本研究以鹿角杯形珊瑚(Pocillopora damicornis)为研究对象,通过气体交换法模拟未来的酸化环境(2100年)研究鹿角杯形珊瑚的钙化率和光合能力(Fv/Fm)对酸化的响应。实验设置两个pH组(分别为7.8和8.1),自然光下进行4周的实验,水温控制在(27.5±1)℃。由于珊瑚等生物的代谢过程(主要是呼吸作用),实验系统的pH昼夜变化显著,酸化处理组和对照组的pH分别介于7.69~7.91和7.99~8.29。鹿角杯形珊瑚的生长率介于1.15%~2.09%/周,酸化对鹿角杯形珊瑚的钙化率和光合效率没有显著的影响,鹿角杯形珊瑚对酸化的敏感度低。对比历史研究数据,本研究的结果进一步表明酸化对造礁珊瑚的影响存在种的特异性。推测鹿角杯形珊瑚对酸化的抗性可能与该珊瑚在有光的条件下能够利用HCO-3以及能够上调钙化位点的pH有关。这种特异性的pH缓冲能力使得珊瑚能维持钙化位点钙质基质高的文石饱和度(Ωarag),因此能以小的额外能耗提高造礁珊瑚的钙化率。  相似文献   

20.
王晓杰  肖潇  李超  岳娜 《海洋学报》2015,37(12):116-122
本文在实验室模拟近期海洋酸化水平,对海洋酸化对海水青鳉鱼(Oryzia melastigma)胚胎骨骼发育的影响进行了初步研究。实验中,通过往实验水体中充入一定浓度CO2气体酸化海水。对照组CO2分压为450×10-6,两个处理组CO2浓度分别为1 160×10-6和1 783×10-6,对应的水体pH值分别为8.14,7.85和7.67。将海水青鳉鱼受精卵放入实验水体中至仔鱼孵化出膜,对初孵仔鱼经骨骼染色、显微拍照,挑取了仔鱼头部、躯干及尾部骨骼染色清晰的28个骨骼参数的长度进行了显微软件测量及数据统计分析。结果发现,酸化处理对实验鱼所测量的骨骼长度影响均不显著。因此推测,未来100~200年间海洋酸化对海水青鳉鱼的胚胎及初孵仔鱼的骨骼发育没有显著影响。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号